This invention concerns a heat transfer assembly for a motor vehicle with a fin/tube block including flat tubes and corrugated ribs. All tube ends of the flat tubes are widened to achieve a flat and flush contact. Two collection containers are installed at opposite tube ends of the fin/tube block. The collection containers grip flush over the tube ends, as well as over two side parts, which extend at least over the length of the fin/tube block. The side parts connect to opposite sides of the fin/tube block.
One heat transfer assembly is described in unpublished German application DE 19,543,986.4. This heat transfer assembly has a fin/tube block that consists of numerous flat tubes and corrugated ribs arranged between the flat tubes. The tube ends of the flat tubes are widened at the front side of the fin/tube block in a free square section. The length of the tube ends lie flush on the neighboring flat tubes so that a tube end packet is formed at front and rear sides of the fin/tube block. This tube end packet is gripped over the sides by a collection container dimensioned in such a way that it can be installed to close off the tubes and be flush with the narrow sides of the tube ends. Side parts are arranged on the sides of the fin/tube block. The side parts can be attached to the outside or inside of the closed side areas of the collection containers.
A primary object of the present invention is to provide a heat transfer assembly of the kind described above that has a simplified construction and, therefore, is easier to manufacture.
This object is attained by holding each collection container open, with respect to the longitudinal axis, at its side areas, and by having each of the side parts include end sections at its opposite ends that close off the open side areas of the collection container. The solution provided by the invention makes it possible to considerably simplify the structure of the collection containers, since they must no longer have closed side areas. Closure of the side areas is carried out by the end sections of the side parts. The invention provides for the requirements of a mechanical heat transfer assembly permitting a considerably more economical manufacture. The cost of production of the heat transfer assembly is reduced by the simpler construction of the collection container with open front areas. A functional closing off of the side areas of the collection container is obtained by attaching the side parts to the fin/tube block. Simple positioning and alignment of the individual components of the heat transfer assembly are made possible in this way. Installation of the collection container onto the fin/tube block can be carried out before installation of the side parts. Alternatively, attachment of the side parts can be carried out before installation of the collection container onto a preassembled unit including side parts and a fin/tube block.
According to one feature of certain preferred embodiments of the invention, each open side area of the collection container has an identical inner contour over at least a certain axial length with respect to the longitudinal axis of each collection container, and each end section of the side parts is provided with an end contour adapted to the inner contour of a corresponding side area so that the end sections can be inserted flush into the side areas. This feature is particularly advantageous when the collection containers, the fin/tube block and the side parts are all made of metal and the collection containers are brazed together with the fin/tube block and the side parts in a mutual brazing process. The collection containers, the side parts, and the fin/tube block are preferably solder-plated at least at their contact sites. The collection containers, the side parts, and the fin/tube block are preferably already attached by actual brazing. The side parts can be held with the aid of tightening straps or some other tightening or tensioning arrangement to the side of the fin/tube block. The end sections of the side parts already close off the side areas of the collection containers in this assembled but not yet brazed unit. By keeping the inner contours of the collection containers identical at a certain axial length, the side parts, and therefore the end sections of the side parts, can still move by a certain axial amount toward the center of the fin/tube block during the brazing process without losing the flush closure in the area of the collection containers. This is particularly advantageous since, during the brazing process, a setting movement of the fin/tube block and of the side parts takes place axis-parallel to the longitudinal axes of the collection containers to the center of the fin/tube block due to the flow of the brazing layers. Consequently, an axial following of the side parts results from a suitable tightening arrangement such as tightening straps. In this way, an extraordinarily exact and function-safe manufacture of the heat transfer assembly is obtained. Additionally, a good seal of the brazing connection is achieved despite the simplified manufacture.
According to another feature of certain preferred embodiments of the invention, the side areas of each collection container are assigned securing elements for axial support, with respect to the longitudinal axis, for the added end section of each side part. These securing elements are particularly advantageous for holding together the individual components of the heat transfer unit before effecting a firm attachment by a corresponding brazing process. The securing elements serve, therefore, to hold together the components of the collection container, the fin/tube block, and the side parts of a premounting stage and, therefore, facilitate a brazing process.
According to a further feature of certain preferred embodiments of the invention, adapted support latches are provided individually as securing elements at the side areas of each collection container, and the latches can be obtained by application of deformation forces and transferred from a narrowing release position of the inner contour of the side area into an axially gripping securing position in each end section. This is a particularly simple and functional feature that is achieved without any additional components.
According to a further feature of certain preferred embodiments of the invention, the end sections of the side parts are provided with corresponding guidance parts at the location of the securing elements so that the securing elements and the guidance parts interlock at the securing position. The securing elements and the guidance parts correspond to each other in such a manner that, in addition to an axial securing of the side parts onto the collection containers, the collection containers themselves are secured against a loss, in the longitudinal direction, of the fin/tube block, and therefore along the longitudinal direction of the flat tubes. As a result, an accurate positioning of all the components of the heat transfer with respect to each other is accomplished.
Finally, according to yet a further feature of certain preferred embodiments of the invention, the side parts include side profiles as well as end profiles rigidly connected to the side profiles, and the end profiles form the end sections and are installed at the front ends of the side profiles as an elongation of the same. In this way, it is possible to structure the side profiles as simple longitudinal profiles in a strand press process or a bending process. Consequently, the manufacturing costs of the side parts can be reduced.